1. Field of the Invention
The present invention relates to an inkjet printer configured to perform maintenance appropriately on all of a plurality of inkjet heads, when performing the maintenance operation by using a maintenance unit common to the plurality of inkjet heads.
2. Description of the Related Art
An inkjet printer is detachably provided with ink cartridges storing respective colors of ink. The inkjet printer prints an image or character on a sheet by supplying ink to an inkjet head from the ink cartridges and discharging the ink on the sheet from nozzles of the inkjet head.
With respect to an ink cartridge, there are many cases where a use period is set as a time period during which the quality of ink is assured. Therefore, a general inkjet printer calculates an expiration date, based on the manufacturing date and the use period stored in the ink cartridge, and when the expiration date of the ink cartridge being used has passed, displays a warning of the fact.
In addition, when an ink cartridge is within a predetermined period (near life) before the expiration date, it is preferable to perform printing by increase in frequency and strength of maintenance such as purging of the inkjet head, although it is possible to continue printing without immediately changing the ink cartridge.
Patent Literature 1 (Japanese Patent Application Laid-Open Publication No. 2006-212868) discloses a technique relating to an inkjet registering apparatus including a recovery unit configured to perform maintenance of a head, a storage unit configured to store information of ink, and a determination unit configured to determine ink deterioration by using the storage unit, wherein the determination unit changes the content of processing by the recovery unit as the ink deteriorates.
The inkjet registering apparatus according to Patent Literature 1 determines ink deterioration for each type of ink based on the ink information and changes the content of processing by the recovery unit (maintenance unit) as the ink deteriorates, and thus the apparatus is assumed to have a recovery unit for each type of ink.
However, the provision of a recovery unit for each type of ink makes the configuration of the apparatus complicated, which results in the increase in production cost. Therefore, an apparatus that is provided with a recovery unit common to a plurality of types of ink and that simultaneously performs maintenance of a plurality of inkjet heads has become the mainstream.
For example, there exists an inkjet printer configured to simultaneously perform a purge operation on a plurality of inkjet heads by providing an air chamber common to a plurality of types of ink and controlling the internal pressure of the air chamber.
It is not possible to apply, to such an inkjet printer, the technique of Patent Literature 1 that changes the content of processing by the recovery unit (maintenance unit) for each type of ink based on ink information, and thus it has not been possible to appropriately perform maintenance such as a purge operation. On condition that pieces of information of all types of ink are integrated into a single parameter, the parameter is not always set so as to allow purge operation to be appropriately performed on all the ink heads. Accordingly, there has been a possibility that purge operation cannot be appropriately performed on all the ink heads, resulting in insufficient purge operation, and thus an adverse effect on the image quality such as discharge failure is caused.